OS4K — FT8 activity observed at SO8OO

DXCC entity inferred from callsign: Belgium Most frequent locator attributed to this token: JO21

Receiver-side FT8 activity involving OS4K, decoded by SO8OO in southeastern Poland. 6,175 FT8 messages attributed to this token as transmitter, on 60m, 40m, 20m, across 96 UTC dates in the available aggregate history. Observed between 2026-06-06 and 2026-10-05.

These are automated observations at the SO8OO receiver, not an official contact log. Times are UTC. Attribution follows decoded FT8 message structure: CQ uses the first token and directed-looking messages use the second. Free text that resembles a directed message can be attributed imperfectly. Summary S/N reflects propagation plus SO8OO receiver, antenna and local-noise conditions. Counts are not adjusted for monitoring outages; transmissions that were not decoded are absent. Inferred entity and location data may be inaccurate for portable, remote or special-event operation.

SO8OO decoded 6,175 FT8 messages attributed to OS4K as the transmitting token by decoded message structure across 96 UTC dates in the available aggregate history. The largest monitored-band total was 20 m (47%), followed by 40 m (45%) and 60 m (8%). The busiest six-hour window was 20:00-02:00 UTC, containing 41% of decodes. Received S/N was mixed across SO8OO's weak, moderate and strong ranges; the estimated median was -14 dB.

Overview

6,175

Messages attributed

UTC dates decoded

1,083

Active 15-min windows

-14 dB

Estimated median S/N

Bands

60m · 470 40m · 2,775 20m · 2,930

First attributed message: 2026-06-06
Last attributed message: 2026-10-05 09:30 UTC

Observed FT8 message patterns

Attributed sample: 6,175 messages
Active dates: 96 UTC dates
Estimated median S/N: -14 dB
Estimated 10th-90th percentile: -23 to +1 dB
Recurring-pattern threshold: Met

SO8OO display ranges among successful decodes: weak (≤ -16 dB) 2,600, moderate (-15 to -9 dB) 1,918, strong (≥ -8 dB) 1,657.

WSJT-X defines S/N reports against a 2,500 Hz reference noise bandwidth. The ranges above are SO8OO receiver-side display categories, not official WSJT-X classes, transmitter-power measurements or estimates of how easy the station is to hear elsewhere. Statistics include only successful decodes on SO8OO's monitored FT8 channels; transmissions that were not decoded are absent.

Frequent counterpart tokens observed at SO8OO

Tokens most often paired with OS4K in decoded directed-looking exchanges:

DL6MRM · Fed. Rep. of Germany ×3 9A2L · Croatia ×2 9A6NTK · Croatia ×2 DG7RBV · Fed. Rep. of Germany ×2 DK2MAX · Fed. Rep. of Germany ×2 DK7MI · Fed. Rep. of Germany ×2 EB7FSB · Spain ×2 IS0KNY · Sardinia ×2 IW1GB · Italy ×2 R2ASV · European Russia ×2 R6OIW · European Russia ×2 SP1BMK · Poland ×2

Attributed messages by UTC hour

Rolling 90-day UTC chart window. Counts follow decoded message structure: the first token for CQ, or the second token in a directed-looking message.

Most frequent locator attributed to OS4K

The map compares the centres and boundaries of the locator field attributed to this token by decoded message structure, 2° × 1° as a Maidenhead square, and SO8OO's six-character receiver square. The separation is not an exact antenna-to-antenna distance or a radio-path length.

Attributed locator: JO21 · 5 decoded messages
SO8OO receiver locator: KN09VW
Locator-centre separation: 1,192 km (approx.)
Last such locator decoded: 2026-09-10 20:37 UTC

A decoded locator can describe portable, remote or special-event operation and is not proof of a permanent station address or transmitter identity.

Observed FT8 exchanges

S/N cells show: decoded at SO8OO / report transmitted by the counterpart. An observed exchange is not a QSL or an official logbook confirmation.

Time UTC	Band	OS4K S/N	Counterpart	Counterpart S/N	Msgs	Capture
10-05 11:23	40m	- / -5	DH6LS	-12 / -	2	✓ Closing fragment
10-05 09:44	40m	- / -10	SP2KW	-2 / -	2	✓ Closing fragment
10-05 09:29	40m	-21 / -	M7WRI	- / -4	3	✓ Closing fragment
10-05 09:18	40m	-17 / -	F4IFC	- / -5	3	Partial capture
10-05 09:16	40m	-18 / -23	9A1BTU	-12 / -	5	✓ Closing observed
10-05 08:54	40m	-24 / -10	9A1DR	-7 / -	3	✓ Closing observed
10-05 08:41	40m	- / -9	IK6ZDE	-18 / -	2	✓ Closing fragment
10-05 08:37	40m	- / -1	DK3HJ	-16 / -	2	✓ Closing fragment
10-05 08:35	40m	- / +3	EI2JD	-22 / -	2	✓ Closing fragment
10-05 08:29	40m	- / +4	DL7PIA	-14 / -	3	Partial capture
10-05 08:07	40m	- / -13	DG5YHK	-16 / -	2	✓ Closing fragment
10-05 07:58	40m	- / -12	DL3NAA	-7 / -	3	Partial capture
10-05 07:57	40m	- / -15	DC1VKR	-6 / -	2	✓ Closing fragment
10-05 07:19	40m	- / -16	OK4SU	-9 / -	2	✓ Closing fragment
10-05 05:25	40m	- / -16	IR8PR	-12 / -	2	Partial capture
10-05 04:18	60m	- / -14	S56KZ	-16 / -	2	✓ Closing fragment
10-05 03:20	60m	-15 / -	WX8W	- / -8	3	Partial capture
10-05 02:31	60m	-22 / -	UA3OO	- / -7	2	Partial capture
10-05 02:28	60m	-19 / -	WB6WUW	- / -14	4	Partial capture
10-05 02:26	60m	-19 / -	I0VHL	- / -8	3	Partial capture
10-05 02:24	60m	-15 / -	F1IQH	- / -9	3	Partial capture
10-05 01:07	60m	- / -22	IZ3XBL	0 / -	2	✓ Closing fragment
10-05 00:55	60m	-22 / -14	KU2A	-14 / -3	3	✓ Full exchange observed
10-04 23:35	60m	-23 / -	ON1JP	-18 / +9	2	Partial capture
10-04 23:34	60m	-23 / -20	WB2NFL	-23 / -	3	✓ Closing observed
10-04 21:54	60m	-23 / -	F1IQH	- / +1	2	Partial capture
10-04 21:50	60m	- / -8	G1HGD	-10 / -	2	✓ Closing fragment
10-04 21:40	60m	-24 / -1	DD7EE	-9 / -1	2	Partial capture
10-04 21:27	60m	- / -6	DG1ASE	-6 / -	2	✓ Closing fragment
10-04 21:07	60m	-20 / -19	EI8GVB	-11 / -2	4	✓ Full exchange observed
10-04 21:02	60m	-22 / -	LX1ER	- / -4	2	Partial capture
10-04 20:58	60m	-24 / -11	G4BHE	-1 / -	2	✓ Closing observed
10-04 20:48	60m	-23 / -	US2YW	- / +8	3	Partial capture
10-04 20:43	60m	-21 / -	DJ6OI/P	- / -1	2	Partial capture
10-04 20:43	60m	- / -7	DL6II	0 / -	2	Partial capture
10-04 20:33	60m	-22 / -10	OZ1NIB	-19 / -	3	✓ Closing observed
10-04 20:31	60m	-22 / -6	DH8BAB	-6 / +4	3	✓ Full exchange observed
10-04 20:27	60m	-21 / -	F1IQH	- / +2	2	Partial capture
10-04 20:26	60m	-20 / -11	DL7DL	0 / -	3	✓ Closing observed
10-04 20:25	60m	-19 / -9	DM5GG	-6 / -1	3	✓ Full exchange observed
10-04 20:08	60m	- / -25	IW1GAL	-16 / -	2	✓ Closing fragment
10-04 20:05	60m	-19 / -2	DJ6OI/P	-13 / -	3	✓ Closing observed
10-04 19:59	60m	-24 / -	DM4EU	- / -10	2	Partial capture
10-04 19:53	60m	-22 / -	DM5GG	- / +3	2	Partial capture
10-04 19:52	60m	-17 / -	IZ5MMK	- / +5	2	Partial capture
10-04 19:41	60m	-23 / -17	DH3SBB	-12 / 0	2	Partial capture
10-04 19:39	60m	-22 / -	OZ9DKJ	- / +1	2	Partial capture
10-04 19:37	60m	- / -6	G0CUZ	-4 / -	2	✓ Closing fragment
10-03 11:55	40m	- / -12	SP9RM	-7 / -	2	✓ Closing fragment
10-03 11:07	40m	- / -15	OK1JGX	-12 / -	2	✓ Closing fragment

Recent FT8 messages decoded at SO8OO

Frequency values are decoder audio offsets in hertz, not RF frequencies.

40m

UTC    dB Audio  Message
091715 -13 1316  OS4K 9A1BTU RR73
091730 -19 2081  9A1BTU OS4K 73
091800 -16 2081  F4IFC OS4K -05 (x3)
092145 -22 2081  F4DIF OS4K RR73
092415 -16 2081  G6XWK OS4K -10
092900 -21 2081  M7WRI OS4K -04 (x3)
094445  -3  603  OS4K SP2KW R-10 (x2)
112345 -13 2358  OS4K DH6LS R-05 (x2)
115130  -6  890  OS4K IN3IBW R-10

60m

UTC    dB Audio  Message
022615 -22 1777  I0VHL OS4K -08 (x3)
022815 -17 1778  WB6WUW OS4K -14 (x4)
023130 -21 1777  UA3OO OS4K -07 (x2)
024430 -24 1778  IU5SCG OS4K +04
032030 -10 1778  WX8W OS4K -08 (x3)
041845 -19 1435  OS4K S56KZ R-14 (x2)

20m

UTC    dB Audio  Message
190845  +1 1660  CT1FIU OS4K +11 (x3)
191015  +4 1659  IK0WCL OS4K +14 (x5)
191245  +6 1659  SA5UTR OS4K -14 (x3)
191415  +2 1659  EC5CFV OS4K +01 (x2)
192145  -9 1659  VE2CXA OS4K -02
120845 -17  906  OS4K PA2MD 73

Decoder S/N history by band

Count-weighted daily averages across messages attributed to this profiled token and successfully decoded at SO8OO, limited to the rolling 90-day UTC chart window.

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